Skeleton code of SparseHistogram

base/metrics/sparse_histogram.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/metrics/sparse_histogram.h"
+
+#include "base/metrics/statistics_recorder.h"
+
+using std::string;
+
+namespace base {
+
+// static
+HistogramBase* SparseHistogram::FactoryGet(const string& name,
+                                           int32 flags) {
+  // TODO(kaiwang): Register and get SparseHistogram with StatisticsRecorder.
+  HistogramBase* histogram = new SparseHistogram(name);
+  histogram->SetFlags(flags);
+  return histogram;
+}
+
+SparseHistogram::~SparseHistogram() {}
+
+void SparseHistogram::Add(Sample value) {
+  base::AutoLock auto_lock(lock_);
+  samples_[value]++;
+}
+
+void SparseHistogram::SnapshotSample(std::map<Sample, Count>* samples) const {
+  base::AutoLock auto_lock(lock_);
+  *samples = samples_;
+}
+
+void SparseHistogram::WriteHTMLGraph(string* output) const {
+  // TODO(kaiwang): Implement.
+}
+
+void SparseHistogram::WriteAscii(string* output) const {
+  // TODO(kaiwang): Implement.
+}
+
+SparseHistogram::SparseHistogram(const string& name)
+    : HistogramBase(name) {}
+
+}  // namespace base